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PROSITE documentation PDOC00443Alpha-galactosidase signature
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PURL: https://purl.expasy.org/prosite/documentation/PDOC00443
α-galactosidase (EC 3.2.1.22) (melibiase) [1] catalyzes the hydrolysis of melibiose into galactose and glucose. In man, the deficiency of this enzyme is the cause of Fabry's disease (X-linked sphingolipidosis). α-galactosidase is present in a variety of organisms. There is a considerable degree of similarity in the sequence of α-galactosidase from various eukaryotic species.
Escherichia coli α-galactosidase (gene melA), which requires NAD and magnesium as cofactors, is not structurally related to the eukaryotic enzymes; by contrast, an Escherichia coli plasmid encoded α-galactosidase (gene rafA) [2] contains a region of about 50 amino acids which is similar to a domain of the eukaryotic α-galactosidases.
α-N-acetylgalactosaminidase (EC 3.2.1.49) [3] catalyzes the hydrolysis of terminal non-reducing N-acetyl-D-galactosamine residues in N-acetyl-α-D-galactosaminides. In man, the deficiency of this enzyme is the cause of Schindler and Kanzaki diseases. The sequence of this enzyme is highly related to that of the eukaryotic α-galactosidases.
We selected, as a signature pattern for these enzymes, the N-terminal part of the conserved domain. The pattern contains two conserved aspartic acid residues which could be involved in the catalytic mechanism.
Note:These proteins belong to families 27 and 36 in the classification of glycosyl hydrolases [4,E1].
Expert(s) to contact by email: Last update:December 2004 / Pattern and text revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Dey P.M. Pridham J.B.C. |
| Title | Biochemistry of -galactosidases. | |
| Source | Adv. Enzymol. 36:91-130(1972). | |
| PubMed ID | 4561015 |
| 2 | Authors | Aslanidis C. Schmid K. Schmitt R. |
| Title | Nucleotide sequences and operon structure of plasmid-borne genes mediating uptake and utilization of raffinose in Escherichia coli. | |
| Source | J. Bacteriol. 171:6753-6763(1989). | |
| PubMed ID | 2556373 |
| 3 | Authors | Wang A.M. Bishop D.F. Desnick R.J. |
| Title | Human alpha-N-acetylgalactosaminidase-molecular cloning, nucleotide sequence, and expression of a full-length cDNA. Homology with human alpha-galactosidase A suggests evolution from a common ancestral gene. | |
| Source | J. Biol. Chem. 265:21859-21866(1990). | |
| PubMed ID | 2174888 |
| 4 | Authors | Henrissat B. |
| Title | A classification of glycosyl hydrolases based on amino acid sequence similarities. | |
| Source | Biochem. J. 280:309-316(1991). | |
| PubMed ID | 1747104 |
| E1 | Title | https://www.uniprot.org/docs/glycosid |
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